Interactions of Pt nanoparticles with molecular components in polymer electrolyte membrane fuel cells: multi-scale modeling approach

Brunello, Giuseppe F.; Lee, Ji Hye; Lee, Seung Geol; Choi, Ji Il; Harvey, David; Jang, Seung Soon

doi:10.1039/c6ra09274h

Cited by 36 publications

(21 citation statements)

References 55 publications

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“…We used the parameters reported by Brunello et al as the vdW parameters that describe metal and nonmetal electrode systems. 46 The total potential energy is given by…”

Section: Computational Detailsmentioning

confidence: 99%

Molecular Dynamics Simulation to Reveal Effects of Binder Content on Pt/C Catalyst Coverage in a High-Temperature Polymer Electrolyte Membrane Fuel Cell

Kwon

Lee

Kim

et al. 2018

ACS Appl. Nano Mater.

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Full atomistic molecular dynamics simulations were performed to provide detailed information on the morphologies of Pt/C catalyst with varying poly(tetrafuoroethylene) (PTFE) binder contents. Changes in the surface configuration and PTFE coverage on Pt particles with changing binder content were examined on the molecular level; this coverage can affect the catalytic performance of Pt particles and PTFE binding. The PTFE binder content in the prepared solutions ranged from 4.0 to 35.1 wt %. From Pt-PTFE pair correlation analysis, the coordination number of this pair increased from 0.43 to 1.23 as the PTFE binder content increased from 4.0 to 35.1 wt %, with a concomitant 40.0 to 84.0% change in coverage over the Pt surface. At low PTFE content, the PTFE binder was dispersed between Pt particles and the carbons on the Pt/C surface to form a triple-phase boundary. Subsequently, Pt particles become increasingly covered by PTFE with increasing binder content. However, no significant changes were observed when the PTFE content exceeded 20.0 wt %; we expect that the catalytic performance of Pt will significantly decrease at PTFE binder contents greater than 20.0 wt %. Considering the Pt-retaining role of the binder, we conclude that the optimum PTFE binder content is less than 20.0 wt % for the ∼2.6 nm diameter Pt particle used in this study. This investigation provides detailed information on polymer properties and electrode morphologies for high-temperature polymer electrolyte membrane fuel cells applications at various PTFE binder contents.

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“…We used the parameters reported by Brunello et al as the vdW parameters that describe metal and nonmetal electrode systems. 46 The total potential energy is given by…”

Section: Computational Detailsmentioning

confidence: 99%

Molecular Dynamics Simulation to Reveal Effects of Binder Content on Pt/C Catalyst Coverage in a High-Temperature Polymer Electrolyte Membrane Fuel Cell

Kwon

Lee

Kim

et al. 2018

ACS Appl. Nano Mater.

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“…The results of this investigation also shed light on further possibilities for computational research on fluorinated carbon-based materials.The DFT calculations were conducted using the Biovia DFT package DMol3 [11], considering the generalized-gradient-approximation (GGA) as well as the Perdew-Burke-Ernzerhof (PBE) exchange and correlation functionals with the double numerical polarized basis set. The GGA-PBE functional has been successfully used to describe the interaction between organic molecules and a carbon-based substrate [12][13][14][15][16][17][18] or an inorganic substrate [19][20][21][22][23]. We used a 5 × 5 × 1 Monkhorst-Pack k-point mesh [24] with a 12.30 Å × 12.30 Å × 15.00 Å periodic boundary condition for the graphene substrate.The adsorption energy (E ads ) was defined aswhere E substrate+gas represents the energy of the entire system, E substrate is the energy of the substrate system alone, and E gas is the energy of the isolated gas molecule.…”

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confidence: 99%

Density functional theory study of CH₄and CO₂adsorption by fluorinated graphene

Hwang¹,

Jeong²,

Lee³

2016

Carbon letters

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Phenomena related to global warming have been of particular interest among researchers, strongly encouraging them to identify various methods of adsorbing contributing gases, such as CH 4 and CO 2 [1,2]. Many adsorbents have been widely proposed and studied to remove greenhouse gases from the atmosphere and protect the environment [3,4]. Carbon-based materials for adsorption are an intriguing subject owing to their very high specific surface area, low weight, and elasticity [5,6]. Among various carbonaceous materials, graphene has attracted much attention from researchers for these reasons; consequently, this material has been empirically and theoretically investigated for possible applications, such as gas sensors [7][8][9][10].Yoon et al. [7] reported the fabrication of a graphene-based CO 2 sensing device that exhibited a fast response to CO 2 and high recyclability due to the weak interaction between CO 2 and graphene. Schrier [8] studied the adsorption of several gas molecules, including CO 2 and CH 4 , on pristine graphene and fully fluorinated graphene at finite temperature. He reported that complete fluorination of graphene is not an effective method for nonpolar gas molecules, such as CH 4 and CO 2 , because the fluorine atom has the lowest polarizability of all atoms, and its dispersion interaction is weak. In addition, for nonpolar molecules, dispersion interactions play the largest role in adsorption. Lee et al. [9] reported the effect of fluorination of a carbon-based substrate on CH 4 /CO 2 separation. They reported that the CO 2 adsorption capacity increased up to 22.5% owing to fluorination with an F/C ratio (%) of 32%-43%.Although experimental studies on the adsorption of gas molecules onto carbon-based substrates have provided much useful information, computational studies at the molecular level can provide detailed information to investigate the interaction between adsorbed gas molecules and substrates. In this study, density functional theory (DFT) calculations were performed to investigate CH 4 and CO 2 adsorption on pristine and fluorinated graphene. This research extends existing knowledge of fluorinated carbon-based materials and their adsorption efficiency from a theoretical viewpoint. The results of this investigation also shed light on further possibilities for computational research on fluorinated carbon-based materials.The DFT calculations were conducted using the Biovia DFT package DMol3 [11], considering the generalized-gradient-approximation (GGA) as well as the Perdew-Burke-Ernzerhof (PBE) exchange and correlation functionals with the double numerical polarized basis set. The GGA-PBE functional has been successfully used to describe the interaction between organic molecules and a carbon-based substrate [12][13][14][15][16][17][18] or an inorganic substrate [19][20][21][22][23]. We used a 5 × 5 × 1 Monkhorst-Pack k-point mesh [24] with a 12.30 Å × 12.30 Å × 15.00 Å periodic boundary condition for the graphene substrate.The adsorption energy (E ads ) was defined aswhere E substrate...

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“…Several molecular dynamics (MD) revealed that ionomer tends to form a thin layer on the surface of catalyst due to specific interactions. [169,170] The group of Jang [171] calculated the binding energies of Nafion with Pt nanoparticles using quantum mechanical DFT and molecular dynamics. It is inferred that sulfonate groups tend to be chemisorbed while CF 3 CF 3 and CF 3 OCF 3 tend to be physisorbed.…”

Section: Interactions With Catalystmentioning

confidence: 99%

Recent Insights on Catalyst Layers for Anion Exchange Membrane Fuel Cells

et al. 2021

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Anion exchange membrane fuel cells (AEMFCs) performance have significantly improved in the last decade (>1 W cm−2), and is now comparable with that of proton exchange membrane fuel cells (PEMFCs). At high current densities, issues in the catalyst layer (CL, composed of catalyst and ionomer), like oxygen transfer, water balance, and microstructural evolution, play important roles in the performance. In addition, CLs for AEMFCs have different requirements than for PEMFCs, such as chemical/physical stability, reaction mechanism, and mass transfer, because of different conductive media and pH environment. The anion exchange ionomer (AEI), which is the soluble or dispersed analogue of the anion exchange membrane (AEM), is required for hydroxide transport in the CL and is normally handled separately with the electrocatalyst during the electrode fabrication process. The importance of the AEI–catalyst interface in maximizing the utilization of electrocatalyst and fuel/oxygen transfer process must be carefully investigated. This review briefly covers new concepts in the complex AEMFC catalyst layer, before a detailed discussion on advances in CLs based on the design of AEIs and electrocatalysts. The importance of the structure–function relationship is highlighted with the aim of directing the further development of CLs for high‐performance AEMFC.

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Interactions of Pt nanoparticles with molecular components in polymer electrolyte membrane fuel cells: multi-scale modeling approach

Abstract: Three phase model consists of Pt nanoparticles, Nafion, and graphite with oxygen, water, and hydronium.

Cited by 36 publications

References 55 publications

Molecular Dynamics Simulation to Reveal Effects of Binder Content on Pt/C Catalyst Coverage in a High-Temperature Polymer Electrolyte Membrane Fuel Cell

Molecular Dynamics Simulation to Reveal Effects of Binder Content on Pt/C Catalyst Coverage in a High-Temperature Polymer Electrolyte Membrane Fuel Cell

Density functional theory study of CH₄and CO₂adsorption by fluorinated graphene

Recent Insights on Catalyst Layers for Anion Exchange Membrane Fuel Cells

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Interactions of Pt nanoparticles with molecular components in polymer electrolyte membrane fuel cells: multi-scale modeling approach

Abstract: Three phase model consists of Pt nanoparticles, Nafion, and graphite with oxygen, water, and hydronium.

Cited by 36 publications

References 55 publications

Molecular Dynamics Simulation to Reveal Effects of Binder Content on Pt/C Catalyst Coverage in a High-Temperature Polymer Electrolyte Membrane Fuel Cell

Molecular Dynamics Simulation to Reveal Effects of Binder Content on Pt/C Catalyst Coverage in a High-Temperature Polymer Electrolyte Membrane Fuel Cell

Density functional theory study of CH4and CO2adsorption by fluorinated graphene

Recent Insights on Catalyst Layers for Anion Exchange Membrane Fuel Cells

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Density functional theory study of CH₄and CO₂adsorption by fluorinated graphene